The present invention relates to an audio band signal transmission system having an audio transmission system which is arranged between a switching system and a cell switching system to transmit an audio band signal via an up line from the cell switching system to the switching system and a down line from the switching system to the cell switching system every connection, and an audio band signal transmission method.
In the prior art, in transmitting the audio signal, such a system is employed that high-efficiency audio compressed coding/decoding processes are performed so as to achieve effective use of the capacity of lines and also one channel is allocated to an audio compressed signal on one line by using time-division multiplex.
However, according to such time-division multiplex, idleness of the lines is generated since channels are still occupied in their idle state. Therefore, in order to achieve the effective use of the lines by such idleness of the lines, the audio signal is divided into compressed-coded audio frames and then transmitted as cells.
According to such system configuration, the method is utilized which enables other lines to utilize the idle transmission lines by transmitting no cell over the idle transmission lines to thus improve statistically a transmission efficiency.
Meanwhile, since compressed-coding cannot be applied to an audio band data signal employed in FAX, MODEM, etc. unlike the audio signal, the audio band data signal is formulated into the cells without compression and then transmitted as it is. Each cell consists of a header area which indicates supplementary information such as an address, data type, etc. and a data area which contains the compressed-coded audio signal or the audio signal per se.
In such above prior art, if the audio band signal transmission system is composed of a large scale network, as disclosed in Patent Application Publication (KOKAI) Hei 9-261239 as shown in FIG. 22, the audio band signal is transmitted to a telephone 103 as a calling destination to pass through relay principal points of a switching system 102 via an audio transmission system 100 and a transmission line 101. At this time, line switching of the audio is carried out at the relay principal points by the switching system 102.
Therefore, the audio transmission system 100 must absorb cell delay variationcell delay variation by delayed-reading the audio band signal, which is subjected to audio compressed coding by an audio compressed coding portion 2B, by using a cell delay variationcell delay variation absorbing buffer 3B, then decode the audio cells into the original state by audio compressed-decoding the audio band signal, which is subjected to cell delay variation absorption by using an audio compressed decoding portion 1B, and then transfer the decoded audio to the switching system 102.
Therefore, according to such audio band signal transmission system in the prior art, the message can be transferred between these telephones 103 in the communication network for the relay transmission, nevertheless various processes such as the audio compressed coding process, the audio compressed decoding process, the cell delay variation absorbing process, etc. are carried out repeatedly by the audio compressed coding portion 2B, the audio compressed decoding portion 1B, the cell delay variation absorbing buffer 3B, etc. respectively every audio transmission system 100 even if such processes are not needed. As a result, there is such a problem that, because of such useless processes, not only degradation of the audio quality but also the delay time in process is increased.
The present invention has been made in view of the above problems, and it is an object of the present invention to provide an audio band signal transmission system and an audio band signal transmission method, which are capable of suppressing a process delay time to the lowest minimum without degradation of audio quality of an audio band signal.
In order to achieve the above object, according to the present invention, there is provided an audio band signal transmission system having an audio transmission system which is arranged between a switching system and a cell switching system, and transmits an audio band signal via an up line from the cell switching system to the switching system and a down line from the switching system to the cell switching system every connection, and has a cell delay variation absorbing buffer for delayed-reading the audio band signal which is transmitted via the up line, comprising a connection identification number inserting portion provided for every connection, for setting a connection identification number which is to be identified every connection, and inserting own connection identification number into an audio band signal cell which is to be transmitted to the switching system via the up line for own connection; a connection identification number detecting portion provided for every connection, for detecting the connection identification number contained in the audio band signal cell which is to be transmitted from the switching system via the down line for own connection; and a routine correcting portion provided for every connection, for correcting a routine before the audio band signal cell, which is transmitted to the switching system via the up line for own connection in response to a predetermined control signal, is input into the connection identification number inserting portion corresponding to this connection, to thus transmit the audio band signal cell via the down line corresponding to own connection without intervention of the switching system and the cell delay variation absorbing buffer; wherein, when one connection identification number detecting portion of connection identification number detecting portions provided for every connection detects the connection identification number via the down line for own connection, it informs the connection identification number detecting portion which corresponds to the connection identification number to output the predetermined control signal.
Therefore, according to the audio band signal transmission system of the present invention, when it is decided in response to notification issued from other connection identification number detecting portion that the audio band signal cell which is to be transmitted to own connection is transmitted via the communication path which is extended over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d in sequence, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the connection identification number inserting portion which corresponds to this connection. Hence, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without intervention of the switching system and the cell delay variation absorbing buffer. As a result, a process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as cell disassembling/assembling processes, etc. generated when the cell is transmitted to the switching system, cell delay variation absorbing process by the cell delay variation absorbing buffer, etc.
Also, according to the present invention, there is provided an audio band signal transmission method of transmitting an audio band signal via an up line from a cell switching system to a switching system and a down line from the switching system to the cell switching system every connection by using an audio transmission system arranged between the switching system and the cell switching system, and then delayed-reading the audio band signal, which is transmitted via the up line, by using a cell delay variation absorbing buffer in the audio transmission system, comprising the steps of setting a connection identification number which is to be identified every connection, and inserting own connection identification number into an audio band signal cell, which is to be transmitted to the switching system via the up line for own connection, by using a connection identification number inserting portion provided for every connection; detecting the connection identification number contained in the audio band signal cell, which is to be transmitted from the switching system via the down line for own connection, by using a connection identification number detecting portion provided for every connection; correcting a routine before the audio band signal cell, which is transmitted to the switching system via the up line for own connection in response to a predetermined control signal, is input into the connection identification number inserting portion corresponding to this connection by using a routine correcting portion provided for every connection, to thus transmit the audio band signal cell via the down line corresponding to own connection without intervention of the switching system and the cell delay variation absorbing buffer; and informing the connection identification number detecting portion, which corresponds to the connection identification number, to output the predetermined control signal by one connection identification number detecting portion of connection identification number detecting portions provided for every connection when such connection identification number detecting portion detects the connection identification number via the down line for own connection.
Therefore, according to the audio band signal transmission method of the present invention, when it is decided in response to notification issued from other connection identification number detecting portion that the audio band signal cell which is to be transmitted to own connection is transmitted via the communication path which is extended over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d in sequence, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the connection identification number inserting portion which corresponds to this connection. Hence, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without intervention of the switching system and the cell delay variation absorbing buffer. As a result, a process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as cell disassembling/assembling processes, etc. generated when the cell is transmitted to the switching system, cell delay variation absorbing process by the cell delay variation absorbing buffer, etc.
There is provided, as set forth in the first aspect of the present invention, an audio band signal transmission system having an audio transmission system which is arranged between a switching system and a cell switching system, and transmits an audio band signal via an up line from the cell switching system to the switching system and a down line from the switching system to the cell switching system every connection, and has a cell delay variation absorbing buffer for delayed-reading the audio band signal which is transmitted via the up line, comprising: a connection identification number inserting portion provided for every connection, for setting a connection identification number which is to be identified every connection, and inserting own connection identification number into an audio band signal cell which is to be transmitted to the switching system via the up line for own connection; a connection identification number detecting portion provided for every connection, for detecting the connection identification number contained in the audio band signal cell which is to be transmitted from the switching system via the down line for own connection; and a routine correcting portion provided for every connection, for correcting a routine before the audio band signal cell, which is transmitted to the switching system via the up line for own connection in response to a predetermined control signal, is input into the connection identification number inserting portion corresponding to this connection, to thus transmit the audio band signal cell via the down line corresponding to own connection without intervention of the switching system and the cell delay variation absorbing buffer; wherein, when one connection identification number detecting portion out of connection identification number detecting portions provided for every connection detects the connection identification number via the down line for own connection, it informs the connection identification number detecting portion which corresponds to the connection identification number to output the predetermined control signal.
Therefore, according to the audio band signal transmission system set forth in the first aspect of the present invention, when it is decided in response to notification issued from other connection identification number detecting portion that the audio band signal cell which is to be transmitted to own connection is transmitted via the communication path which is extended over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d in sequence, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system and the cell delay variation absorbing buffer via the up line for own connection is input into the connection identification number inserting portion which corresponds to this connection. Hence, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without intervention of the switching system and the cell delay variation absorbing buffer. As a result, a process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as cell disassembling/assembling processes, etc. generated when the cell is transmitted to the switching system, cell delay variation absorbing process by the cell delay variation absorbing buffer, etc. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the twenty-first aspect of the present invention.
In an audio band signal transmission system set forth in the second aspect of the present invention, in addition to a configuration according to the first aspect of the invention, the audio transmission system includes a switching system interface portion for transmitting the audio band signal between the switching system and the audio transmission system, a transmission line interface portion for transmitting the audio band signal between the cell switching system and the audio transmission system, and a multiplexing portion arranged between the switching system interface portion and the transmission line interface portion, for transmitting the audio band signal between the switching system and the cell switching system, wherein the switching system interface portion has the cell delay variation absorbing buffer for delayed-reading the audio band signal which is transmitted via the up line.
Therefore, according to the audio band signal transmission system set forth in the second aspect of the present invention, the audio transmission system consists of three portions of the switching system interface portion, the transmission line interface portion, and the multiplexing portion. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the twenty-second aspect of the present invention.
In an audio band signal transmission system set forth in the third aspect of the present invention, in addition to a configuration according to the second aspect of the invention, the multiplexing portion of the audio transmission system contains a connection identification number inserting portion, a connection identification number detecting portion, and a routine correcting portion every connection, and the connection identification number detecting portion outputs the predetermined control signal to the routine correcting portion which corresponds to own connection when it confirms in response to notification from other connection identification number detecting portion that a communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, and the routine correcting portion corrects the routine of the audio band signal from the up line in response to the predetermined control signal to transmit the audio band signal to the down line without intervention of the switching system interface portion and the switching system.
Therefore, according to the audio band signal transmission system set forth in the third aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the switching system interface portion and the switching system. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as the cell disassembling/assembling processes, the cell delay variation absorbing process, etc. generated in the switching system interface portion, the process generated in the switching system, etc. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in twenty-third aspect of the present invention.
In an audio band signal transmission system set forth in the fourth aspect of the present invention, in addition to a configuration according to the third aspect of the invention, the switching system interface portion of the audio transmission system includes a compressed coding portion for compressed-coding the audio band signal transmitted from the switching system via the down line, and a compressed decoding portion for compressed-decoding the audio band signal which is delayed-read by the cell delay variation absorbing buffer.
Therefore, according to the audio band signal transmission system set forth in the fourth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the switching system interface portion and the switching system. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as the cell disassembling/assembling processes, the cell delay variation absorbing process, and the audio compressed coding/decoding processes in the switching system interface portion, the process generated in the switching system, etc. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the twenty-fourth aspect of the present invention.
In an audio band signal transmission system set forth in the fifth aspect of the present invention, in addition to a configuration according to the second aspect of the invention, the switching system interface portion of the audio transmission system contains a connection identification number inserting portion, a connection identification number detecting portion, and a routine correcting portion, all are arranged at a preceding stage of the cell delay variation absorbing buffer, every connection, the connection identification number detecting portion outputs a predetermined control signal to the routine correcting portion which corresponds to own connection when it confirms that a communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, and the routine correcting portion corrects the routine of the audio band signal from the up line in response to the predetermined control signal to thus transmit the audio band signal to the down line without intervention of the cell delay variation absorbing buffer and the switching system.
Therefore, according to the audio band signal transmission system set forth in the fifth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the switching system and the cell delay variation absorbing buffer. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal, and also the switching system interface portion can be disconnected easily from the system at the time of failure or maintenance if this function is attached to the switching system interface portion in place of the multiplexing portion serving as a control system of the audio band signal transmission system. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the twenty-fifth aspect of the present invention.
In an audio band signal transmission system set forth in the sixth aspect of the present invention, in addition to a configuration according to the fifth aspect of the invention, the switching system interface portion of the audio transmission system includes a compressed coding portion for compressed-coding the audio band signal which is transmitted from the switching system via the down line to then transmit a compressed-coded audio band signal to the connection identification number detecting portion, and a compressed decoding portion for compressed-decoding the audio band signal which is delayed-read by the cell delay variation absorbing buffer.
Therefore, according to the audio band signal transmission system set forth in sixth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the switching system and the cell delay variation absorbing buffer. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal, and also the switching system interface portion can be disconnected easily from the system at the time of failure or maintenance if this function is attached to the switching system interface portion in place of the multiplexing portion serving as a control system of the audio band signal transmission system. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the twenty-sixth aspect of the present invention.
In an audio band signal transmission system set forth in the seventh aspect of the present invention, in addition to a configuration according to the second aspect of the invention, the transmission line interface portion of the audio transmission system contains a connection identification number inserting portion, a connection identification number detecting portion, and a routine correcting portion every connection, the connection identification number detecting portion outputs the predetermined control signal to the routine correcting portion which corresponds to own connection when it confirms in response to notification from other connection identification number detecting portion that a communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, and the routine correcting portion corrects the routine of the audio band signal from the up line in response to the predetermined control signal to thus transmit the audio band signal to the down line without intervention of the multiplexing portion, the switching system interface portion, and the switching system.
Therefore, according to the audio band signal transmission system set forth in the seventh aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the multiplexing portion, the switching system interface portion and the switching system. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as the multiplexing process in the multiplexing portion, the cell disassembling/assembling processes and the cell delay variation absorbing process in the switching system interface portion, the process generated in the switching system, etc. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the twenty-seventh aspect of the present invention.
In an audio band signal transmission system set forth in the eighth aspect of the present invention, in addition to a configuration according to the seventh aspect of the invention, the switching system interface portion of the audio transmission system includes a compressed coding portion for compressed-coding the audio band signal which is transmitted from the switching system via the down line, and a compressed decoding portion for compressed-decoding the audio band signal which is delayed-read by the cell delay variation absorbing buffer.
Therefore, according to the audio band signal transmission system set forth in the eighth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the multiplexing portion, the switching system interface portion and the switching system. As a result, the delay time of the audio band signal can be suppressed to the lowest minimum among the audio transmission systems by omitting useless processes such as the multiplexing process in the multiplexing portion, the cell disassembling/assembling processes, the cell delay variation absorbing process, and the audio compressed coding/decoding processes in the switching system interface portion, the process generated in the switching system, etc., and in addition degradation of the audio quality of the audio band signal can be prevented without fail. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the twenty-eighth aspect of the present invention.
In an audio band signal transmission system set forth in the ninth aspect of the present invention, in addition to a configuration according to the first aspect of the present invention, the cell switching system contains a connection identification number inserting portion, a connection identification number detecting portion, and a routine correcting portion every connection, and the connection identification number detecting portion outputs the predetermined control signal to the routine correcting portion which corresponds to own connection when it confirms in response to notification from other connection identification number detecting portion that a communication path for own connection is extended in sequence over xe2x80x9cthe cell switching system, the audio transmission system, the switching system, the audio transmission system, and the cell switching systemxe2x80x9d, and the routine correcting portion corrects the routine of the audio band signal from the up line in response to the predetermined control signal to then transmit the audio band signal to the down line without intervention of the audio transmission system and the switching system.
Therefore, according to the audio band signal transmission system set forth in the ninth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal can be transmitted to the down line, without the intervention of the audio transmission system and the switching system. As a result, the delay time of the audio band signal can be suppressed to the lowest minimum among the audio band signal transmission systems by omitting useless processes such as the cell transmitting process, the cell multiplexing process, the cell delay variation absorbing process, and the cell disassembling/assembling processes in the audio transmission system, the process generated in the switching system, etc., and in addition degradation of the audio quality of the audio band signal can be prevented without fail. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the twenty-ninth aspect of the present invention.
In an audio band signal transmission system set forth in the tenth aspect of the present invention, in addition to a configuration according to the ninth aspect of the invention, the audio transmission system includes a compressed coding portion for compressed-coding the audio band signal which is transmitted from the switching system via the down line, and a compressed decoding portion for compressed-decoding the audio band signal which is delayed-read by the cell delay variation absorbing buffer.
Therefore, according to the audio band signal transmission system set forth in the tenth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal can be transmitted to the down line, without the intervention of the audio transmission system and the switching system. As a result, the delay time of the audio band signal can be suppressed to the lowest minimum among the audio band signal transmission systems by omitting useless processes such as the audio compressed coding/decoding processes in the audio transmission system, the process generated in the switching system, etc., and also degradation of the audio quality of the audio band signal can be prevented without fail. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirtieth aspect of the present invention.
There is provided, as set forth in the eleventh aspect of the present invention, an audio band signal transmission system having an audio transmission system which is arranged between a switching system and a cell switching system, and transmits an audio band signal via an up line from the cell switching system to the switching system and a down line from the switching system to the cell switching system every connection, and has a cell delay variation absorbing buffer for delayed-reading the audio band signal which is transmitted via the up line, comprising: a connection identification number cell transmitting portion provided for every connection, for setting a connection identification number which is to be identified every connection, and transmitting a control cell containing own connection identification number, which is paired with the audio band signal cell, separately from the audio band signal cell which is to be transmitted to the switching system via the up line for own connection; a connection identification number cell detecting portion provided for every connection, for detecting a control cell which is paired with the audio band signal cell to be transmitted from the switching system via the down line for own connection, and then detecting the connection identification number contained in the control cell; and a routine correcting portion provided for every connection, for correcting a routine before the audio band signal cell, which is transmitted to the switching system via the up line for own connection in response to a predetermined control signal, is input into the connection identification number cell transmitting portion corresponding to this connection, to thus transmit the audio band signal cell via the down line corresponding to this own connection without intervention of the switching system and the cell delay variation absorbing buffer; wherein, when one connection identification number cell detecting portion out of connection identification number detecting portions provided for every connection detects the connection identification number via the down line for own connection, it informs the connection identification number cell detecting portion which corresponds to the connection identification number to output the predetermined control signal.
Therefore, according to the audio band signal transmission system set forth in the eleventh aspect of the present invention, when it is decided in response to notification issued from other connection identification number detecting portion that the audio band signal cell which is to be transmitted to own connection is transmitted via the communication path which is extended over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d in sequence, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system and the cell delay variation absorbing buffer via the up line for own connection is input into the connection identification number inserting portion which corresponds to this connection. Hence, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without intervention of the switching system and the cell delay variation absorbing buffer. As a result, a process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as cell disassembling/assembling processes, etc. generated when the cell is transmitted to the switching system, cell delay variation absorbing process by the cell delay variation absorbing buffer, etc. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-first aspect of the present invention.
In an audio band signal transmission system set forth in the twelfth aspect of the present invention, in addition to a configuration according to the eleventh aspect of the invention, the audio transmission system includes a switching system interface portion for transmitting the audio band signal between the switching system and the audio transmission system, a transmission line interface portion for transmitting the audio band signal between the cell switching system and the audio transmission system, and a multiplexing portion arranged between the switching system interface portion and the transmission line interface portion, for transmitting the audio band signal between the switching system and the cell switching system, wherein the switching system interface portion has the cell delay variation absorbing buffer for delayed-reading the audio band signal which is transmitted via the up line.
Therefore, according to the audio band signal transmission system set forth in the twelfth aspect of the present invention, the audio transmission system consists of three portions of the switching system interface portion, the transmission line interface portion, and the multiplexing portion. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-second aspect of the present invention.
In an audio band signal transmission system set forth in the thirteenth aspect of the present invention, in addition to a configuration according to the twelfth aspect of the invention, the multiplexing portion of the audio transmission system contains a connection identification number cell transmitting portion, a connection identification number cell detecting portion, and a routine correcting portion every connection, the connection identification number cell detecting portion outputs the predetermined control signal to the routine correcting portion which corresponds to own connection when it confirms in response to notification from other connection identification number cell detecting portion that a communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, and the routine correcting portion corrects the routine of the audio band signal from the up line in response to the predetermined control signal to transmit the audio band signal to the down line without intervention of the switching system interface portion and the switching system.
Therefore, according to the audio band signal transmission system set forth in the thirteenth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the switching system interface portion and the switching system. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as the cell disassembling/assembling processes, the cell delay variation absorbing process, etc. generated in the switching system interface portion, the process generated in the switching system, etc. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-third of the present invention.
In an audio band signal transmission system set forth in the fourteenth aspect of the present invention, in addition to a configuration according to the thirteenth aspect of the invention, the switching system interface portion of the audio transmission system includes a compressed coding portion for compressed-coding the audio band signal which is transmitted from the switching system via the down line, and a compressed decoding portion for compressed-decoding the audio band signal which is delayed-read by the cell delay variation absorbing buffer.
Therefore, according to the audio band signal transmission system set forth in the fourteenth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the switching system interface portion and the switching system. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as the cell disassembling/assembling processes, the cell delay variation absorbing process, and the audio compressed coding/decoding processes in the switching system interface portion, the process generated in the switching system, etc. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-fourth aspect of the present invention.
In an audio band signal transmission system set forth in the fifteenth aspect of the present invention, in addition to a configuration according to the twelfth aspect of the invention, the switching system interface portion of the audio transmission system contains a connection identification number cell transmitting portion, a connection identification number cell detecting portion, and a routine correcting portion, all are arranged at a preceding stage of the cell delay variation absorbing buffer, every connection, the connection identification number cell detecting portion outputs a predetermined control signal to the routine correcting portion which corresponds to own connection when it confirms in answer to notification from other connection identification number cell detecting portion that a communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, and the routine correcting portion corrects the routine of the audio band signal from the up line in answer to the predetermined control signal to thus transmit the audio band signal to the down line without intervention of the cell delay variation absorbing buffer and the switching system.
Therefore, according to the audio band signal transmission system set forth in the fifteenth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the switching system and the cell delay variation absorbing buffer. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal, and also the switching system interface portion can be disconnected easily from the system at the time of failure or maintenance if this function is attached to the switching system interface portion in place of the multiplexing portion serving as a control system of the audio band signal transmission system. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-fifth aspect of the present invention.
In an audio band signal transmission system set forth in the sixteenth aspect of the present invention, in addition to a configuration according to the fifteenth aspect of the invention, the switching system interface portion of the audio transmission system includes a compressed coding portion for compressed-coding the audio band signal which is transmitted from the switching system via the down line to then transmit a compressed-coded audio band signal to the connection identification number cell detecting portion, and a compressed decoding portion for compressed-decoding the audio band signal which is delayed-read by the cell delay variation absorbing buffer.
Therefore, according to the audio band signal transmission system set forth in the sixteenth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the switching system and the cell delay variation absorbing buffer. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal, and also the switching system interface portion can be disconnected easily from the system at the time of failure or maintenance if this function is attached to the switching system interface portion in place of the multiplexing portion serving as a control system of the audio band signal transmission system. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-sixth aspect of the present invention.
In an audio band signal transmission system set forth in the seventeenth aspect of the present invention, in addition to a configuration according to the twelfth aspect of the invention, the transmission line interface portion of the audio transmission system contains a connection identification number cell transmitting portion, a connection identification number cell detecting portion, and a routine correcting portion every connection, the connection identification number cell detecting portion outputs the predetermined control signal to the routine correcting portion which corresponds to own connection when it confirms in response to notification from other connection identification number cell detecting portion that a communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, and the routine correcting portion corrects the routine of the audio band signal from the up line in response to the predetermined control signal to thus transmit the audio band signal to the down line without intervention of the multiplexing portion, the switching system interface portion, and the switching system.
Therefore, according to the audio band signal transmission system set forth in the seventeenth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the multiplexing portion, the switching system interface portion and the switching system. As a result, the process delay time can be suppressed to the lowest minimum without degradation of the audio quality of the audio band signal by omitting useless processes such as the multiplexing process in the multiplexing portion, the cell disassembling/assembling processes and the cell delay variation absorbing process in the switching system interface portion, the process generated in the switching system, etc. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-seventh aspect of the present invention.
In an audio band signal transmission system set forth in the eighteenth aspect of the present invention, in addition to a configuration according to the seventeenth aspect of the invention, the switching system interface portion of the audio transmission system includes a compressed coding portion for compressed-coding the audio band signal which is transmitted from the switching system via the down line, and a compressed decoding portion for compressed-decoding the audio band signal which is delayed-read by the cell delay variation absorbing buffer.
Therefore, according to the audio band signal transmission system set forth in the eighteenth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal cell can be transmitted via the down line corresponding to this own connection, without the intervention of the multiplexing portion, the switching system interface portion and the switching system. As a result, the delay time of the audio band signal can be suppressed to the lowest minimum among the audio transmission systems by omitting useless processes such as the multiplexing process in the multiplexing portion, the cell disassembling/assembling processes, the cell delay variation absorbing process, and the audio compressed coding/decoding processes in the switching system interface portion, the process generated in the switching system, etc., and in addition degradation of the audio quality of the audio band signal can be prevented without fail. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-eighth aspect of the present invention.
In an audio band signal transmission system set forth in the nineteenth aspect of the present invention, in addition to a configuration according to the eleventh aspect of the invention, the cell switching system contains a connection identification number cell transmitting portion, a connection identification number cell detecting portion, and a routine correcting portion every connection, the connection identification number cell detecting portion outputs the predetermined control signal to the routine correcting portion which corresponds to own connection when it confirms in response to notification from other connection identification number cell detecting portion that a communication path for own connection is extended in sequence over xe2x80x9cthe cell switching system, the audio transmission system, the switching system, the audio transmission system, and the cell switching systemxe2x80x9d, and the routine correcting portion corrects the routine of the audio band signal from the up line in response to the predetermined control signal to then transmit the audio band signal to the down line without intervention of the audio transmission system and the switching system.
Therefore, according to the audio band signal transmission system set forth in the nineteenth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal can be transmitted to the down line, without the intervention of the audio transmission system and the switching system. As a result, the delay time of the audio band signal can be suppressed to the lowest minimum among the audio band signal transmission systems by omitting useless processes such as the cell transmitting process, the cell multiplexing process, the cell delay variation absorbing process, and the cell disassembling/assembling processes in the audio transmission system, the process generated in the switching system, etc., and in addition degradation of the audio quality of the audio band signal can be prevented without fail. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the thirty-ninth aspect of the present invention.
In an audio band signal transmission system set forth in the twentieth aspect of the present invention, in addition to a configuration according to the nineteenth aspect of the invention, the audio transmission system includes a compressed coding portion for compressed-coding the audio band signal which is transmitted from the switching system via the down line, and a compressed decoding portion for compressed-decoding the audio band signal which is delayed-read by the cell delay variation absorbing buffer.
Therefore, according to the audio band signal transmission system set forth in the twentieth aspect of the present invention, when it is confirmed in response to notification issued from other connection identification number detecting portion that the communication path for own connection is extended in sequence over xe2x80x9cthe audio transmission system, the switching system, and the audio transmission systemxe2x80x9d, the routine of the cell is corrected before the audio band signal cell which is to be transmitted to the switching system via the up line for own connection is input into the identification number inserting portion which corresponds to this connection. Therefore, the audio band signal can be transmitted to the down line, without the intervention of the audio transmission system and the switching system. As a result, the delay time of the audio band signal can be suppressed to the lowest minimum among the audio band signal transmission systems by omitting useless processes such as the audio compressed coding/decoding processes in the audio transmission system, the process generated in the switching system, etc., and also degradation of the audio quality of the audio band signal can be prevented without fail. In this case, the similar advantage can also be achieved by the audio band signal transmission method set forth in the fortieth aspect of the present invention.